49 Cub Rod Bearing Question

[ctltmp]

Hi everyone. I'm trying to figure out what rod bearings to order. I mic'd the journals and got 1.490,1.490,1.489,1.490.

On the bearings is this
455SB
Fm
GN
010 US

Would all this add up to a .010 under bearing size? From what I measured it's not quite -.010 and I don't want to build it too tight.

Any knowledge is appreciated in advance. Thanks

[tst]

a stock rod journal is 1.499 so yours is .010 undersize, the bearing you have is .010 under size, plastic gauge the bearing when you reassemble to verify correct clearance

[ctltmp]

What is the acceptable clearance for the bearing to journal fit?
Thanks

[Clark Thompson]

no more than .001.

[ctltmp]

I talked to the previous owner. He did the last overhaul on the engine. He said the crank shaft had never been machined and the put standard bearings in it, so the plot thickens.

[Eugene]

Per the service manual. Connecting rod insert to rod journal "Bearing running clearance - inch -----.002 - .003".

Your mic measurements and the number on the back of the insert indicated that the crankshaft has been turned at some time.

[Slim140]

:?
I talked to the previous owner. He did the last overhaul on the engine. He said the crank shaft had never been machined and the put standard bearings in it, so the plot thickens.

I would say it had already been ground and he didn't know it. He just got "replacement" bearings and didn't know they were .010" undersized. Just a guess on my part.

[ctltmp]

Here's a picture of one of the bearings that came out of it if this help's figure out anything.

Thanks to everyone for helping!

[Slim140]

Here's a picture of one of the bearings that came out of it if this help's figure out anything.

Thanks to everyone for helping!

20160725_193442.jpg

The 010 US means it's .010" undersized, just like everyone is telling you. What else do you need help figuring?

[ctltmp]

I guess no other help required just now. I appreciate the help. I guess I'm just having a hard time accepting uncle Ed tells me he used std. bearings when he had overhauled it the last time.Just can't get me head wrapped around that part of it. But it is what it is.

I'll order the .010 under bearings and plastigage the clearance when I get the parts in.

Thanks again.

[Jim Becker]

Turning the rod journals does not necessarily mean the main journals were also turned. It may have standard size mains. Have you looked at them yet?

[ctltmp]

Yes, the mains looked good, but I have not measured the main journals. The main bearings also looked nice and to be honest it wasn't in my plan to even replace the mains. After all this and some reconsideration, maybe I should?

Back on the rod bearings, I made a call to one of the oldest tractor guys I know about the bearings. He agrees with you all on my original question that whoever claims they did what, the bearings that came out of it were .010 over. If anyone is in the Northern WV or Western PA area his name is Dale Reeseman and he's probably done hundreds of tractors, sells parts and supplies and he's well up in age. Some don't like him but he's always been fair with me.

My goal here is to get a rebuild that runs well and looks decent. I know that it won't be perfect when it's done. This Cub will probably never see a plow in the ground again (although I love to plow!). It may plow some snow here and there at most if all goes well. If it weren't my wife's grandpa's tractor I most probably wouldn't be doing any of this probably. I did my last tractor 10 or 12 years ago when I still had the farm. This old girl found me, I didn't go looking.

[Eugene]

The main bearings also looked nice and to be honest it wasn't in my plan to even replace the mains. After all this and some reconsideration, maybe I should?

One main bearing at a time. Plastigauge, check the numbers stamped on the back of the bearing. Replace the bearing cap with the bearing. Move on to the next main bearing.

If the clearance was at the maximum recommended, I would replace the main bearings. Excessive bearing clearance will cause a reduction in oil pressure.

[ctltmp]

Thanks everyone. I'll check the mains too. I guess if I'm in this deep I might as well go all the way............

[Scrivet]

Either uncle Ed is mistaken or someone else has been in there that uncle Ed doesn't know about. Clearly the bearings you took out aren't standard size no matter how many people you talk to. Maybe he's thinking about a different engine or maybe it's been to long ago to remember clearly. So what did you have for lunch two weeks ago thursday? How long ago was it that he did the engine work????????